Plastic components, particularly automotive dashboards or trim assemblies having bosses that receive self-tapping metal screws to apply a clamping load to a support that secures the component in position. In virgin plastic bosses which have the screws applied for the first time, the interfacial friction between the screw threads and the tapped grooves of the plastic boss sometimes may not be sufficiently high to prevent loosening of the screws over long periods of vibration.
More significantly, when the screws are improperly torqued during installation, the tapped grooves within the plastic may be stripped so that there is little holding power for providing the desired clamping load. Since the plastic component usually has bosses which are tubular with a wall thickness generally in the range of 1.5-2.0 mm, there is little mass left to either install a larger self-tapping screw that would create new and larger thread grooves, or install an expandable anchor insert in the stripped hole with sufficient boss stiffness to promote gripping by the screw.